James Rouse is the director of new independent movie Downhill, which tells the story of four childhood friends who reunite to walk the Coast to Coast path from Cumbria to Yorkshire - bringing plenty of emotional baggage with them.

Here James tells Country Walking where the idea came from, how the epic trek was filmed, and why the White Lion in Patterdale is a great place for a meltdown...

Where did the idea come from?

We wanted to make a British road movie, but we soon realised the problem with that: Britain isn't big enough.

You can pretty much get anywhere in a car within two days, which doesn't give you much scope to tell a developing story. So then we thought, slow it down, and make it a road movie on foot.

I used to walk a lot with my parents when I was a kid, so I definitely had memories of what it was like to undertake a big mission in the outdoors, and I'd often wondered what it would be like to go back out there as a grown-up, as Gordon does in the film. So we had a film about a walk.

Why the Coast to Coast?

We settled on the C2C because we loved the idea of walking right across the country from sea to sea, and showing off the spectacular countryside of England. It seemed like the perfect challenge that would appeal to this group of men at this particular point in their lives, particularly Gordon as the leader and real walking enthusiast.

As a director I love putting my characters through situations that will bring out the best and worst in them, and the Coast to Coast certainly does that to people. It can't help but bring out sides to yourself that you've never seen coming. You learn about yourself as you're walking.

How did you research it?

We read everything we could, and then me and Torben Betts the writer and Benji Howell the producer did a section of it as research. It was the section from Patterdale to Shap, and I've heard many people say it's the toughest section because of all the mountainous terrain it goes through. Sure enough it was very hard, we got wet and we were pathetically badly equipped.

I'm pretty good with a map but as soon as the mist comes down and you can't see where the path is, it becomes a different world. We were very grateful to some real walkers who came past with one of those GPS devices to show us where we should have been. Naturally we then decided that our characters would NOT have one of those.

We also decided that we would have to understand how it felt to try and do a big walk after a big night of boozing, as the characters keep doing. We chose the White Lion in Patterdale, which turns up in the film. That might sound like a fun assignment, and obviously it partly was - but the morning after was total punishment. We made sure the actors understood how painful it was to drag yourself out when you've really overdone it the night before.

So we put these characters, who are going through a very tumultuous time in their lives, into this fantastic landscape and took them right out of the comfort zones they normally occupy. The landscape, and what it demands of them, just pushes the buttons that release the tension they're all coping with.

How was the filming?

We made an active choice to make the cast do as much of the journey as filming would allow. In film-making it's very rare to shoot scenes in the order they'll eventually appear but we did that, starting in St Bees and going across to Robin Hood's Bay. It was an immersive experience and the characters grew with the journey.

Obviously there was a script to start with but it was very much script rather than Scripture - the actors were free to go where the characters and the landscapes took them, and watching that happen was fascinating.

It was a three-week shoot in June and we had rain every day. It was unbelievable; you'd hope for one day free of rain but it never came. But we did get some lovely breaks where the sun came out - mainly on the days when the girls' characters joined the group, which was strangely apt. And actually I don't think the film suffers for the rain; it creates quite a true and real atmosphere and reflects the mood these characters are in.

The trailer makes it look like a real scream, but there's a lot of emotion in the film; did you want it to be as much as drama as a comedy?

There are moments of comedy but it wasn't intended to be an out-and-out comic film. It was more important for it to have a human side, a heart and a soul, and to be something that maybe stays with you for a while after you've seen it. Funny things will happen on a walk like that with people like this, but serious and angry and tender things will happen too, so as I say it was a case of wanting to show everything that the walk would do to the characters.

There's a character - Julian - who has shades of that great Lake District adventurer Withnail, from Withnail and I. Was that deliberate?

A few people have said that. It wasn't a conscious thing at all, I'd never want to ape such a wonderful character as Withnail. The character is actually more based around (actor) Ned Dennehy's own personality - I hope he won't mind me saying that!

We see a lot of real places in the film - pubs, cafes, guesthouses etc. Was there a warm welcome for a bedraggled film crew?

Oh god yes! I'm so grateful to all the places where we filmed, which are all authentic places that I hope Coast to Coast walkers will recognise - pubs and farms in Ennerdale, Shap, Keld, Reeth and so on. There's a full list at the end of the film and we'd recommend all of them.

There's a big dramatic scene in the White Lion in Patterdale; we had a corner of the pub to film in but normal life was carrying on everywhere else, so when Keith has his big meltdown, the reactions in the background are completely genuine. It's great to watch.

Any favourite places on the journey?

Ennerdale and Borrowdale; they were just incredibly beautiful. And we shot a big scene at Honister that I love very much; I'm sure keen walkers will recognise the landscapes there. The character Steve has this wonderful childish tantrum at that point, halfway up a harsh, brutal-looking crag with this amazing view behind him. It was June but it was bitterly, bitterly cold; the crew were in six layers but the cast were only wearing the basic stuff they had all along, so they really were freezing.

There's also a swimming scene in a river in the Yorkshire Dales; that was even colder. To show the cast I wouldn't ask them to do anything I wouldn't do myself, I stood in the water at the start to talk them through the scene. It was absolutely freezing, but I had to make like I was completely calm and the end of my speech was totally natural and casual, rather than me desperately wanting to get out of there as quickly as possible.

It feels like quite a personal film for you.

Yes, we all literally threw ourselves into this film and I'm so proud of what the cast and crew accomplished. From a personal point of view, I've put my life, soul and savings into it so it's an emotional journey for me. But I didn't make it for the art or for a personal quest, I made it because I hope people will enjoy it.

And if it inspires one person to do the Coast to Coast, I'll be absolutely delighted. England should be seen, and I think that walk is the perfect way to see it - even if it rains.

* Downhill opens in UK cinemas on May 30th. Find more about it, including a competition and the trailer, at www.downhill-the-movie.com

* The new issue of Country Walking features a complete guide to walking the Coast to Coast without the hassles encountered by the Downhill characters - plus five other amazing ways to go coast-to-coast across the UK! It's on sale now.